These infant seats comprise the very seat itself, a backrest with lateral protections, and a liftable headrest being also generally provided with lateral protections, said infant seats being designed for children of different ages, particularly for those of more than one year of age.
The headrest forms a separate piece being adapted to be fitted to the backrest in an upwardly shiftable arrangement in order to thus be in a position to be adapted to the child's height and to thus still protect this latter's head, the lateral protections of the backrest nevertheless remaining in a stationary arrangement and hence not properly fulfilling their function because their low position does not offer an adequate protection for the lateral shifting motions of the child such as those possibly occurring during the sudden changes of direction of the motorcar, for example.